Drill bit



lPatented Aug. 6, 1940` UNITED STATES PATENT OFFICE.

DRILL BIT Applicationpctober 12, "1939, Serial No. 299,055

5 Claims.

' This invention relates to bearings, and more particularly t a general 'bearing assembly utithat the essential bearing parts must all be internal, and protected from injury and contamination by the sand, grit, etc., of the well by the cone cutter, which forms a substantially unbroken protective covering. This is especially true where ball bearings',and a bushing -with a ball race, tted on the spindle, is used. If the balls are inserted into the race through an aperture in the bushing, this aperture must be plugged by a member which will conform to the shape of the raceway and will not rotate on its axis or otherwise change its position, otherwise the free movement of the balls will be hampered. Further, the bushing must be fastened on the spindle by some-means such as a nut, wholly Within the interior of the cone cutter, which may be tightened and loosened at will, and .will not interfere with thel rotation of the cutter. I am aware that various forms of cone cutter bearingsl havey been developedb ut so far as I am aware, no one has solved the above problems by means similarto those embodied in my invention.

The primary object of my invention is to in-v crease the efliciency of bearings for cone cutters.

Another object is the attainment of smooth and uninterrupted ball race on a cone cutter bearing bushing.

Still another object is a secure and easily at the bore of the bushing, av spindle onto which the bushing is placed, said spindle having a keyway to receive said ley and hold the plug in position and prevent rotation on its axis and thereby maintain a smooth and unbroken ball race, a nut on the end of the shaft to hold the bushing, and a hole through the surface ofthe cone cutter to permit the entry of a pin to screw or unscrew the nut.

Further objects and features will become evi- (Cl. Z55-71) dent from the following disclosure when taken in connection with the accompanying drawing, in which- Fig. 1 is a longitudinal cross-section of a cone cutter organization embodying my invention; 5 and Fig. 2 is'a fragmentary cross-section, taken on the line 2-2 of Fig. 1.

Referring to the ldrawing in detail, a. drill bit 'body designated generally at-ID has, made inftegral therewith, a spindle II havinga Areduced portion I2, a forward screw-threaded portion I3, and a keywayv I4 in the larger portion of the spindle, the purpose of which will be hereinafter disclosed.

Securely fitted on the stud shaft II is a bush. ing I5 which has roller bearing races I6 and I'I, and a ball race I8. There is a bore I9; of a size .to receive ball bearings drilled through the bushing into the ball race I8, whose purpose is to permit the balls to be inserted into the race. Closure for this bore is effected by the plug 20, whose upper portion, as may be also lseen in Fig. 2, is shaped to form a part of the race. In order to prevent the plug from rotating on its axis and thereby spoiling the continuity of the race,. and' also to prevent rotation of' the bushing on, the shaft, there is formed onthe bottom end of the plug 20 a key 2| which ts in the keyway I4 of the shaft and thereby holds the bushing and the plug against rotation. \f

Cone cutter 22 is iitted on the bushing, and has roller raceways and a ball race to correspond to the bushing raceways I6, I1, and I8. The cutter has an aperture 23 in its nose for a purpose 'disclosed below?.

In assembling the device, the 'roller bearings are placed in the races I6 and Ilfof the bushing, in heavy grease to hold them in position. "The cone cutter 22 is then `iitted, on the bushing, and Vball bearings 24 are inserted throughA the bore I9 into the ball race v I8 following which the plug 20 is inserted inthe bora-and the bushing-,is fitted Von the shaft II so that the key 2| 'enters the keyway I4. A nut 25 is shaped to fit in the nose of the cutter 2 2, normally rotatable therein, the nut having a hole 26 in its side. `In'order to screw upthe nut', a removable pin 21 is inserted through the aperture 23 lin the nose of the `cutter into the hole 26 in the nut, and the cutter is'v '50 rotated to rotate the nut. Whenthe nut has been securely tightened, the pin is removed and the cutter is free to. rotate. l

Accordingly, it will be 'seen that the nut 25 holds the bushing I5s`ecurely in place, so that 55 keyway the action of the plug with the key and keyway produce a smoothly working ball bearing by which' the cone cutterK is mounted against axial movement and may be rotated with a minimum of friction. I do not wish to be limited to4 the specific embodiment set out herein, but only by the scope of the appended claims.

I claim:

1. In a cone cutter bearing, a stud shaft, a bushing on said shaft, a ball bearing race on the bushing, a bore through the bushing leading into said race 'and of a size to receive ball bearings, a Y

cone cutter mounted .on the bushing, said cutter having a" ball race corresponding to the race on the bushing, ball bearings in said races, and means for plugging said bore, said means conforming to the shape of said ball race and also coacting with the shaft to hold the means from axial movement and the bushing from rotationA ings therein, and a plug in said bore whose upper end is shaped to form a part of said ball race and whose lower end is formed with a key positioned in said keyway.

3. In a cone cutter bearing, a stud shaftextending from a bit and comprising an enlarged portion adjacent the bit and a reduced portion adjacent the end, a keyway on the enlarged portion, a bushing fitted on the shaft with itsoutside surface having a ball bearing race, a bore through the bushing of a size to receive ball bearings and leading into said race, a 'plug through the bore Whose upper end forms a part of said race and whose lower end is formed with a key positioned in said keyway, a cone cutter mounted on the bushing, a. ball bearing race on the inside of said cutter corresponding with the ball race of the bushing and. ball bearings therebetween, and means for holding the bushing on the shaft.

4. In a cone cutter bearing, a shaft, a threaded portion on the free end of the shaft, a4 bushing fitted on the shaft and of such length that the bushing does not cover the threaded portion, ball bearing and roller bearing'races on the outside surface of said bushing, a cone cutter mounted on roller bearings and ball bearings in said races against axial movement with respect to the bushing, a nut separate from the bushing on the threaded portion of the shaft, an aperture in the side of the nut, and abore in the nose of the cutter positioned to register with the aperture in the nut so that a removable tool may be inserted therein to turn the nut.

5. In a cone cutter bearing, a stud shaft made integral with a bit and comprising an enlarged portion adjacent the bit and a reduced portion adjacent the free end thereof, a threaded portion at the free end thereof, a keyway in the enlarged portion, a bushing tted on the stud shaft with its outside surface havingl a large for the bore whose upper end forms a part of said race and whose lower' end is formed with a key positioned in the aforementioned keyway, a cone cutter, races on the inside surface vof the cone cutter to correspond with the races o n the bushing, said cutter being journaled on the bushing by ybearings in the races; a nut on the threaded portion of the shaft, said nut having an aperture in its side, and a hole in the nose of the cone cutter in position to register with the aperture of the nut so that a removable pin may be inserted therein to turn the nut.

BENJAMIN I-IANLY. 

